/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.skatiger.jrove.compiler;

import java.util.ArrayList;
import java.util.List;
import java.util.Stack;

import javax.el.ELException;

import org.skatiger.jrove.JroveHandler;
import org.skatiger.jrove.el.ELText;
import org.skatiger.jrove.tag.CompositeHandler;
import org.skatiger.jrove.tag.Tag;
import org.skatiger.jrove.tag.TagAttribute;
import org.skatiger.jrove.tag.TagException;
import org.skatiger.jrove.util.StringUtils;

final class TextUnit extends CompilationUnit {

    private final static String trimRight(String s) {
        int i = s.length() - 1;
        while (i >= 0 && Character.isWhitespace(s.charAt(i))) {
            i--;
        }
        if (i == s.length() - 1) {
            return s;
        } else {
            return s.substring(0, i + 1);
        }
    }

    private final StringBuilder buffer;

    private final StringBuilder textBuffer;

    private final List<Instruction> instructionBuffer;

    private final Stack<Tag> tags;

    private final List<Object> children;

    private boolean startTagOpen;

    private final String alias;

    private final String id;

    public TextUnit(String alias, String id) {
        this.alias = alias;
        this.id = id;
        this.buffer = new StringBuilder();
        this.textBuffer = new StringBuilder();
        this.instructionBuffer = new ArrayList<Instruction>();
        this.tags = new Stack<Tag>();
        this.children = new ArrayList<Object>();
        this.startTagOpen = false;
    }

    @Override
    public void addChild(CompilationUnit unit) {
        // if we are adding some other kind of unit
        // then we need to capture our buffer into a UITextHandler
        this.finishStartTag();
        this.flushBufferToConfig(true);
        this.children.add(unit);
    }

    private void addInstruction(Instruction instruction) {
        this.flushTextBuffer(false);
        this.instructionBuffer.add(instruction);
    }

    @Override
    public JroveHandler createJroveHandler() {
        this.flushBufferToConfig(true);

        if (this.children.size() == 0) {
            return LEAF;
        }

        JroveHandler[] h = new JroveHandler[this.children.size()];
        Object obj;
        for (int i = 0; i < h.length; i++) {
            obj = this.children.get(i);
            if (obj instanceof JroveHandler) {
                h[i] = (JroveHandler) obj;
            } else {
                h[i] = ((CompilationUnit) obj).createJroveHandler();
            }
        }
        if (h.length == 1) {
            return h[0];
        }
        return new CompositeHandler(h);
    }

    public void endTag() {
        Tag tag = (Tag) this.tags.pop();

        this.addInstruction(new EndElementInstruction(tag.getQName()));

        if (this.startTagOpen) {
            this.buffer.append("/>");
            this.startTagOpen = false;
        } else {
            this.buffer.append("</").append(tag.getQName()).append('>');
        }
    }

    private void finishStartTag() {
        if (this.tags.size() > 0 && this.startTagOpen) {
            this.buffer.append(">");
            this.startTagOpen = false;
        }
    }

    protected void flushBufferToConfig(boolean child) {

        // NEW IMPLEMENTATION
        if (true) {

            this.flushTextBuffer(child);

            int size = this.instructionBuffer.size();
            if (size > 0) {
                try {
                    String s = this.buffer.toString();
                    if (child) {
                        s = trimRight(s);
                    }
                    ELText txt = ELText.parse(s);
                    if (txt != null) {
                        Instruction[] instructions = (Instruction[]) this.instructionBuffer
                                .toArray(new Instruction[size]);
                        this.children.add(new UIInstructionHandler(this.alias,
                                this.id, instructions, txt));
                        this.instructionBuffer.clear();
                    }

                } catch (ELException e) {
                    if (this.tags.size() > 0) {
                        throw new TagException((Tag) this.tags.peek(),
                                e.getMessage());
                    } else {
                        throw new ELException(this.alias + ": "
                                + e.getMessage(), e.getCause());
                    }
                }
            }

            // KEEP THESE SEPARATE SO LOGIC DOESN'T GET FUBARED
        } else if (this.buffer.length() > 0) {
            String s = this.buffer.toString();
            if (s.trim().length() > 0) {
                if (child) {
                    s = trimRight(s);
                }
                if (s.length() > 0) {
                    try {
                        ELText txt = ELText.parse(s);
                        if (txt != null) {
                            if (txt.isLiteral()) {
                                this.children.add(new UILiteralTextHandler(txt
                                        .toString()));
                            } else {
                                this.children.add(new UITextHandler(this.alias,
                                        txt));
                            }
                        }
                    } catch (ELException e) {
                        if (this.tags.size() > 0) {
                            throw new TagException((Tag) this.tags.peek(),
                                    e.getMessage());
                        } else {
                            throw new ELException(this.alias + ": "
                                    + e.getMessage(), e.getCause());
                        }
                    }
                }
            }
        }

        // ALWAYS CLEAR FOR BOTH IMPL
        this.buffer.setLength(0);
    }

    private void flushTextBuffer(boolean child) {
        if (this.textBuffer.length() > 0) {
            String s = this.textBuffer.toString();

            if (child) {
                s = trimRight(s);
            }
            if (StringUtils.isNotEmpty(s)) {
                ELText txt = ELText.parse(s);
                if (txt != null) {
                    if (txt.isLiteral()) {
                        this.instructionBuffer.add(new LiteralTextInstruction(
                                txt.toString()));
                    } else {
                        this.instructionBuffer.add(new TextInstruction(
                                this.alias, txt));
                    }
                }
            }

        }
        this.textBuffer.setLength(0);
    }

    public boolean isClosed() {
        return this.tags.empty();
    }

    public void startTag(Tag tag) {

        // finish any previously written tags
        this.finishStartTag();

        // push this tag onto the stack
        this.tags.push(tag);

        // write it out
        this.buffer.append('<');
        this.buffer.append(tag.getQName());

        this.addInstruction(new StartElementInstruction(tag.getQName()));

        TagAttribute[] attrs = tag.getAttributes().getAll();
        if (attrs.length > 0) {
            for (int i = 0; i < attrs.length; i++) {
                String qname = attrs[i].getQName();
                String value = attrs[i].getValue();
                this.buffer.append(' ').append(qname).append("=\"")
                        .append(value).append("\"");

                ELText txt = ELText.parse(value);
                if (txt != null) {
                    if (txt.isLiteral()) {
                        this.addInstruction(new LiteralAttributeInstruction(
                                qname, txt.toString()));
                    } else {
                        this.addInstruction(new AttributeInstruction(
                                this.alias, qname, txt));
                    }
                }
            }
        }

        // notify that we have an open tag
        this.startTagOpen = true;
    }

    @Override
    public String toString() {
        return "TextUnit[" + this.children.size() + "]";
    }

    public void write(String text) {
        this.finishStartTag();
        this.textBuffer.append(text);
        this.buffer.append(text);
    }

    public void writeComment(String text) {
        this.finishStartTag();

        ELText el = ELText.parse(text);
        if (el.isLiteral()) {
            this.addInstruction(new LiteralCommentInstruction(text));
        } else {
            this.addInstruction(new CommentInstruction(el));
        }

        this.buffer.append("<!--" + text + "-->");
    }

    public void writeInstruction(String text) {
        this.finishStartTag();
        ELText el = ELText.parse(text);
        if (el.isLiteral()) {
            this.addInstruction(new LiteralXMLInstruction(text));
        } else {
            this.addInstruction(new XMLInstruction(el));
        }
        this.buffer.append(text);
    }
}
